Analysis of tdh gene and its adjacent loci of Vibrio parahaemolyticus isolates from seafoods
副溶血弧菌海产品分离株tdh基因及其临近区域结构分析

Abstract: Objective] To analyze the structural characteristics of tdh gene and its adjacent loci of Vibrio parahaemolyticus isolates from seafoods. Methods] Long distance PCR and genome walking were used to amplify the DNA sequences flanking the tdh gene, and the sequences were analyzed by blastn against the NCBI database. Results] The genetic structure of tdh-adjacent loci (VPA1312-VPA1327) from isolate ZS34 was similar to that of the reference strain RIMD2210633, with the nucleotide identity of 98.3%. The tdh gene of isolates FJ14 and WZ64 was located in the loci different from the reference strain and ZS34, and showed high nucleotide similarity to tdh3 gene. In the genome of isolate FJ14, tdh was 15kb away from the trh-ure cluster, with IS-like elements and transposase genes inserted therein. Isolate WZ64 lacked trh gene, but also harbored IS-like elements upstream of tdh. Conclusion] The tdh-adjacent loci of V. parahaemolyticus seafood isolates exhibit high diversity, an additional evidence of lateral gene transfer in this particular species.